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Showing papers on "Phosphotungstic acid published in 1986"


Journal ArticleDOI
TL;DR: Both plasma membrane and tonoplast fractions were estimated to be about 90% pure and neither appeared to be contaminated by the other by more than 3% as determined from marker activities.
Abstract: A procedure is described whereby highly purified fractions of plasma membrane and tonoplast were isolated from hypocotyls of dark-grown soybean ( Glycine max L. var Wayne) by the technique of preparative free-flow electrophoresis. Fractions migrating the slowest toward the anode were enriched in thick (10 nanometers) membranes identified as plasma membranes based on ability to bind N -1-naphthylphthalamic acid (NPA), glucan synthetase-II, and K + -stimulated, vanadate-inhibited Mg 2+ ATPase, reaction with phosphotungstic acid at low pH on electron microscope sections, and morphological evaluations. Fractions migrating farthest toward the anode (farthest from the point of sample injection) were enriched in membrane vesicles with thick (7-9 nanometers) membranes that did not stain with phosphotungstic acid at low pH, contained a nitrate-inhibited, Cl-stimulated ATPase and had the in situ morphological characteristics of tonoplast including the presence of flocculent contents. These vesicles neither bound NPA nor contained levels of glucan synthetase II above background. Other membranous cell components such as dictyosomes (fucosyltransferase, latent nucleosidediphosphate phosphatase), endoplasmic reticulum vesicles (NADH- and NADPH- cytochrome c reductase), mitochondria (succinate-2( p -indophenyl)-3- p -nitrophenyl)-5-phenyl tetrazolium-reductase and cytochrome oxidase) and plastids (carotenoids and monogalactosyl diglyceride synthetase) were identified on the basis of appropriate marker constituents and, except for plastid thylakoids, had thin (

81 citations


Journal ArticleDOI
TL;DR: The type I collagen fibril has been used as a model system to study the mechanism of negative staining and the results point to the ‘bulkiness’ (average cross-sectional area or ‘plumpness’) of amino acid side chains as the dominant stain-excluding factor determining the small-scale distribution of stain along the collagenfibril.

15 citations



Journal ArticleDOI
TL;DR: The role played by the hydratation degree of certain components from epoxy-embedded tissues on the reaction mechanisms observed with some dyes and electron contrasting agents is briefly discussed.

6 citations


Journal ArticleDOI
TL;DR: A phosphotungsten reagent is developed which functions as efficiently as the uranium reagent in the precipitation of RNA in the determination of ribonuclease activity.

5 citations


Patent
11 Dec 1986
TL;DR: In this paper, the authors proposed a method to obtain a titled substance by reacting an aromatic hydrocarbon with an alkenyl aromatic hydrocarbons by the use of a heteropoly acid or its salt as a catalyst.
Abstract: PURPOSE:To obtain in high selectivity economically the titled substance useful as a solvent, an electrical insulating oil, a plasticizer, etc., by reacting an aromatic hydrocarbon with an alkenyl aromatic hydrocarbon by the use of a heteropoly acid or its salt as a catalyst. CONSTITUTION:In obtaining the titled substance (e.g., mixture of a compound shown by the formula I and a compound shown by the formula II) by reacting an aromatic hydrocarbon (e.g., tetralin) with an alkenyl aromatic hydrocarbon (e.g., styrene), a heteropolyacid selected from phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, and silicomolybdic acid or its salt is used as a catalyst. Preferably the catalyst such as silica, etc., is supported on a carrier such as silica, etc., and dried at 100-300 deg.C.

3 citations


Patent
11 Jun 1986
TL;DR: In this article, the authors proposed a method to obtain a titled polymer having low corrosiveness and suitable as a lubricant, etc., by polymerizing a specific cyclic ether using a heteropolyacid as a catalyst in the presence of water of an amount to form two liquid phases consisting of an organic phase containing the raw material and the liquid phase including the catalyst and recovering the polymer from the organic phase.
Abstract: PURPOSE:To obtain the titled polymer having low corrosiveness and suitable as a lubricant, etc., by polymerizing a specific cyclic ether using a heteropolyacid as a catalyst in the presence of water of an amount to form two liquid phases consisting of an organic phase containing the raw material and the liquid phase containing the catalyst and recovering the polymer from the organic phase. CONSTITUTION:A >=5-membered cyclic ether (e.g. tetrahydrofuran) is homopolymerized, or the ether is copolymerized with various cyclic ethers, or copolymerized with a >=5-membered cyclic ether and a polyhydric alcohol, using a heteropolyacid (e.g. phosphotungstic acid) or its salt as a catalyst, in the presence of water of an amount to form two liquid phases consisting of an organic phase containing the raw material and the liquid phase containing the catalyst, in a binary liquid phase system wherein the catalyst liquid phase accounts for >=10vol% of the whole liquid phases in the polymerizer 1. After the reaction, the reaction mixture is subjected to the phase- separation in the phase-separation tank 2. The polymer is separated from the organic phase containing the raw material, and the catalyst-containing liquid phase is circulated to the polymerizer 1 and reused.

3 citations


Journal ArticleDOI
TL;DR: In this article, the catalytic activity of some solid acidic catalysts was tested in the depolymerization of paraldehyde, and it was found that the activities of sulfonated ion exchange resin and mounted phosphotungstic acid strongly exceed the activity of silica-alumina and other oxide catalysts.
Abstract: The catalytic activity of some solid acidic catalysts was tested in the depolymerization of paraldehyde. It was found that the activities of sulfonated ion exchange resin and mounted phosphotungstic acid strongly exceed the activity of silica-alumina and other oxide catalysts. By means of Bronsted relationship, the differences in HO of the surfaces were estimated.

2 citations